Production of actinorhodin-related "blue pigments" by Streptomyces coelicolor A3(2)

Abstract

The genetically well-known strain Streptomyces coelicolor A3(2) produces the pH indicator (red/blue) antibiotic actinorhodin, but not all the ''blue pigment'' produced by this strain is actinorhodin. When the organism was subjected to various nutrient limitations (ammonium, nitrate, phosphate, or trace elements), and also during growth cessation caused by a relatively low medium pH, blue pigment production was initiated but the pigment and its location varied. At pH 4.5 to 5.5, significant formation of actinorhodin occurred and was located exclusively intracellularly. At pH 6.0 to 7.5 a different blue pigment was produced intracellularly as well as extracellularly. It was purified and identified as ␥-actinorhodin (the lactone form of actinorhodin). Analysis of act mutants of S. coelicolor A3(2) confirmed that both pigments are derived from the act biosynthetic pathway. Mutants with lesions in actII-ORF2, actII-ORF3, or actVA-ORF1, previously implicated or suggested to be involved in actinorhodin export, were impaired in production of ␥-actinorhodin, suggesting that synthesis of ␥-actinorhodin from actinorhodin is coupled to its export from the cell. However, effects on the level of actinorhodin production were also found in some mutants.

Microbial production of textile grade pigments

“…Based on the morphological and biochemical analysis (Berd, 1973), strain B1 and V1 were identified as Streptomyces sp, C1 and G1 as Actinomyces sp., S1 as Serratia, O1 as Rhodococcus sp., P1 and Y1as Nocardia sp., (Tables 1 and 2). In additon to that, morphological characters like sporulation (Bystrykh et al,1996), diffusible pigments (Shirling and Gottlieb, 1966) support the conclusion (Tables 1 and 2). …”

Forty years of genetics with Streptomyces: from in vivo through in vitro to in silico

“…While cloning the act genes demonstrated close linkage of biosynthetic structural genes, the finding that Streptomyces parvulus containing the act cluster produced actinorhodin without killing itself (Malpartida & Hopwood, 1984) provided indirect evidence that a resistance gene had also been cloned ; the basis of actinorhodin self-resistance, while probably in some way reflecting antibiotic export (Bystrykh et al, 1996), is still not well understood. In contrast, the methylenomycin gene cluster, on SCP1, was proved to contain resistance as well as biosynthetic and regulatory genes.…”

New ΦBT1 site-specific integrative vectors with neutral phenotype in Streptomyces

“…Undecylprodigiosin and actinorhodin were quantified spectrophotometrically according to Tsao et al (1985) and Bystrykh et al (1996). In order to measure the total amount of actinorhodin (intracellular and extracellular), cells were ruptured in their culture medium by adding KOH 0.1 N. Cellular debris was discarded by centrifugation, and actinorhodin was quantified spectrophotometrically with a UV/visible spectrophotometer (Shimadzu, Model UV-1240), applying the linear Beer-Lambert relationship to estimate concentration (e640 = 25,320).…”